Information recording medium on which sector data generated from ECC block is recorded, information recording apparatus for recording sector data, and information reproduction apparatus for reproducing sector data

ABSTRACT

An information recording medium includes a management area where management information is recorded and a plurality of physical sector areas used to record a plurality of physical sector data blocks, which are generated by combining some data contained in a plurality of ECC blocks.

[0001] rewritable DVDs have been created. The standards describe an ECCblock structure appended with parity codes for error correction as adata structure to be recorded on an optical disk (information recordingmedium). In existing DVDs, data having an ECC block structure common toboth read-only and rewritable optical disks is recorded. Also, theapplication standards that describe the recording format in theapplication layer upon recording AV (Audio/Video) information or streaminformation on existing DVDs have been created.

[0002] In the physical standards, the minimum unit of user informationto be recorded on an optical disk is 2048 bytes, and this recording unitis called a physical sector. Data in the physical sector include a dataID that records a sector number or the like, an error detection code IED(Data ID Error Detection code) for the data ID, user information, and anerror detection code EDC (Error Detection Code) for data in the physicalsector. As an error correction scheme for improving the reliability ofdata recorded on an optical disk, a “REED Solomon product code” schemeis adopted, and an ECC block structure appended with PI (inner-codeparity) data and PO (outer-code parity) data is formed. One ECC blockconsists of data for 16 sectors. The technique that pertains to the ECCblock structure is disclosed in Jpn. Pat. Appln. KOKAI Publication No.10-172243.

[0003] In the present specifications, data contents or data structureincluding a data ID and parity data is called “data”, and userinformation (=Main data) to be recorded is called “information”. Also,data contents or information contents directly recorded in a physicalsector on an optical disk are called “physical sector data” (=physicalsector data block) or “physical sector information”. One item ofphysical sector information has a size of 2048 bytes.

[0004] The logical standards define the data structure associated withuser information to be recorded on an optical disk when viewed from thehost computer side which is connected to an interface of an informationreproduction or recording apparatus. The minimum unit to be exchangedbetween the host computer and information reproduction or recordingapparatus is defined as a logical sector, and in the presentspecification, the contents of user information corresponding to thelogical sector are called logical sector information. The logical sectorinformation has a size of 2048 bytes in correspondence with that of thephysical sector information.

[0005] The contents of the logical sector information basically matchthose of the physical sector information. However, since the physicallayer defined in the physical standard and the logical layer defined inthe logical standard are different layers, the contents of the physicalsector information may be different from those of the logical sectorinformation in practice. That is, the host computer and informationreproduction or recording apparatus exchange information using 2048-bytelogical sector information as a minimum unit, and information obtainedby processing this logical sector information may be recorded asphysical sector information on an optical disk.

[0006] The minimum unit of video object information or audio objectinformation transferred between the host computer and informationreproduction or recording apparatus is also 2048 bytes in correspondencewith the logical sector size. According to the application standards,video object information and audio object information are broken up into2048 bytes, and are multiplexed in the format of a pack structure as aminimum unit upon being recorded on an optical disk. That is,audio/video information to be recorded on a recording medium issegmented along the time axis, and video packs that store video objectinformation and audio packs that store audio object information aredistributed while being mixed. In this case, the video or audio packinformation itself corresponds to the contents of the logical sectorinformation.

[0007] The minimum unit of recording stream information is called anSOBU (Stream Object Unit), and one SOBU size is defined to be 32 logicalsectors or 2 ECC blocks.

[0008] In existing DVDs, error correction can be made up to a maximumburst error length of 6 mm on an optical disk. In next-generation DVDs,the data bit length on an optical disk (recording medium) becomes smallsince the data recording density increases. Assume that the data bitlength is proportional to the wavelength of light used in an opticalhead of the reproduction or recording/reproduction apparatus, and isinversely proportional to NA (Numerical Aperture). In this case, if thenext-generation DVD has an optical wavelength of 405 nm and NA=0.85compared to the existing DVD having an optical wavelength of 650 nm andNA=0.65, the error-correctable burst error length on an optical disk(recording medium) is considerably reduced to 2.9 mm.

6×(405÷650)×(0.65÷0.85)=2.9

[0009] Therefore, the next-generation DVD requires a technical means forassuring an error-correctable burst error length of 6 mm or more as inthe current DVD.

[0010] When the correctable burst error length is greatly improved forthe next-generation DVD while exploiting the REED Solomon product codetechnique as the ECC block structure, the following problems (1) to (2)are posed, and it is impossible to greatly improve the correctable bursterror length by only changing the size of the REED Solomon product codeof the existing DVD.

[0011] (1) The maximum size of a REED Solomon product code that correctserrors for respective unit bytes is limited to 256 rows×256 columns. Inthe existing DVD, the maximum size is 208 rows×182 columns. The existingDVD has an optimal structure within the limit range of 256 rows×256columns, and it is difficult to greatly improve the correctable bursterror length by merely changing the size.

[0012] (2) The main data information encoding efficiency cannot begreatly reduced compared to the existing DVD. It is possible to improvethe correctable burst error length by increasing the PO size in an ECCblock. But when this is done, redundancy which depends on the PO sizeincreases and the main data information encoding efficiently dropsconsiderably. The existing DVD has main data information encodingefficiency of 87% as well as redundant data such as a data ID and thelike in the physical data. Hence, in the next-generation DVD, anencoding efficiency of around 87% needs to be assured.

[0013] (3) An appropriate physical data structure must be guaranteed. Asa method of greatly improving the correctable burst error length and ofassuring high main data information encoding efficiency, a method oflargely increasing the PO size and reducing the PI size accordingly maybe readily devised. However, in order to assure high-speed data accesson an optical disk, the data ID must be arranged at the head in thephysical sector data, and an interleaved arrangement of PO data inrespective physical sectors is required for this purpose. However, toattain this, it becomes difficult to change the PO size to an arbitraryvalue.

BRIEF SUMMARY OF THE INVENTION

[0014] It is an object of the present invention to provide aninformation recording medium, information recording apparatus, andinformation reproduction apparatus which can solve the aforementionedproblems.

[0015] In order to solve the aforementioned problems and to achieve theabove object, an information recording medium, information recordingapparatus, and information reproduction apparatus of the presentinvention have the following arrangements.

[0016] (1) An information recording medium of the present inventioncomprises a management area where management information is recorded,and a plurality of physical sector areas used to record a plurality ofphysical sector data blocks, which are generated by combining some datacontained in a plurality of ECC blocks.

[0017] (2) An information recording apparatus of the present inventioncomprises generation section configured to generating a plurality of ECCblocks, and recording section configured to generating a plurality ofphysical sector data blocks by combining some data contained in theplurality of ECC blocks, and recording the plurality of physical sectordata blocks on a plurality of physical sector areas on the informationrecording medium.

[0018] (3) An information reproduction apparatus of the presentinvention comprises read-out section configured to reading out theplurality of physical sector data blocks from the plurality of physicalsector areas on the information recording medium, and reproductionsection configured to reproducing data by generating the plurality ofECC blocks from the plurality of readout physical sector data blocks.

[0019] Additional objects and advantages of the invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0020] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate embodiments of theinvention, and together with the general description given above and thedetailed description of the embodiments given below, serve to explainthe principles of the invention.

[0021]FIG. 1 shows the data structure of physical sector data generatedfrom a plurality of ECC blocks, the relationship between physical sectorinformation and logical sector information, and the like;

[0022]FIG. 2 shows the data structure of physical sector data recordedon an information recording medium, and the relationship between aplurality of physical sector data and a plurality of (two) correspondingECC blocks;

[0023]FIG. 3 shows the data structure of an ECC block upon completion ofrow interleave when one sector data consists of an odd number of rows;

[0024]FIG. 4 shows the data structure of physical sector data generatedfrom a single ECC block, the relationship between physical sectorinformation and logical sector information, and the like;

[0025]FIG. 5 shows the data structure of physical sector data recordedon an information recording medium, and the relationship between aplurality of physical sector data and a single corresponding ECC block;

[0026]FIG. 6 is a schematic block diagram showing the arrangement of aninformation recording/reproduction apparatus according to an embodimentof the present invention;

[0027]FIG. 7 is a flowchart for explaining generation of an ECC blockand recording of physical sector data;

[0028]FIG. 8 shows the data structure of sector data when one sectordata is formed of an odd number of rows;

[0029]FIG. 9 shows an example of re-arrangement of sector data when onesector data is formed of an odd number of rows;

[0030]FIG. 10 shows the data structure of sector data when one sectordata is formed of an odd number of rows;

[0031]FIG. 11 shows a state wherein the sector block shown in FIG. 10 ishorizontally segmented into two blocks, and outer and inner code partiesare appended to the respective blocks;

[0032]FIG. 12 shows the data structure of physical sector data generatedfrom an ECC block upon completion of row interleave shown in FIG. 3;

[0033]FIG. 13 shows a state wherein data contained in physical sectordata undergoes zigzag recording;

[0034]FIG. 14 shows examples of the arrangement of an outer code (PO) inphysical sector data;

[0035]FIG. 15 shows the data structure of an ECC block upon completionof row interleave when one sector data is formed of an even number ofrows;

[0036]FIG. 16 shows the data structure of sector data when one sectordata is formed of an even number of rows;

[0037]FIG. 17 shows an example of re-arrangement of sector data when onesector data is formed of an even number of rows;

[0038]FIG. 18 shows the data structure of sector data when one sectordata is formed of an even number of rows;

[0039]FIG. 19 shows a state wherein the sector block shown in FIG. 18 ishorizontally segmented into two blocks, and inner and outer codeparities are appended to the respective blocks; and

[0040]FIG. 20 shows the data structure of physical sector data generatedfrom an ECC block upon completion of row interleave shown in FIG. 15.

DETAILED DESCRIPTION OF THE INVENTION

[0041] Preferred embodiments of the present invention will now bedescribed with reference to the accompanying drawings.

[0042] Basic features of the present invention are as follows.

[0043] 1) Physical sector data to be recorded on an optical disk issegmented into small pieces, and segmented data is sequentially arranged(interleaved) in n (n is a positive value equal to or larger than 2) ECCblocks.

[0044] 2) It is devised to always arrange the data ID at the headposition of each physical sector data before or after the interleaveprocess. As a result, even when access is made for respective physicalsectors, address information can be quickly read out, and high-speedaccess can be attained.

[0045] This embodiment exemplifies a case of “n =₂”, but the contents ofthe present invention are not limited to this, and can be applied to acase of n=3 or n=4.

[0046] As a method of arranging one physical sector data in a pluralityof ECC blocks, the present invention has proposed the following twomethods.

[0047] Method 1: Physical sector information matches logical sectorinformation. One physical sector data is segmented into rows includingPI, the data for respective rows are respectively assigned to n (n≧2)ECC blocks, and the total of the number of rows including PI in onephysical sector data and the number of PO rows is an integer multiple ofn.

[0048] Method 2: All pieces of information in one logical sector arecontained in a single ECC block. Logical sector data contained indifferent ECC blocks undergo an interleave process by alternatelyexchanging rows of these blocks for respective rows, and a dataarrangement obtained as a result of that process is recorded on anoptical disk as physical sector data.

[0049] An outline of method 1 will be explained first using FIGS. 1 and2.

[0050] An optical disk (information recording medium 9) has a physicalsector area 9 a and management area 9 b. The management area 9 b recordsmanagement information. Data recorded in the physical sector area 9 awill be described below. AV information or stream information, which istransferred continuously, is broken up into small pieces, which areconverted into pack structures appended with pack headers, and thesepacks are recorded on a plurality of physical sector areas 9 a assuredon the optical disk. More specifically, as shown in (a) of FIG. 1, videoinformation and audio information are transferred while being arrangedalong the time axis in the form of video packs 1-0 to 1-3, and audiopacks 2-0 and 2-1. Each of the video packs 1-0 to 1-3 and audio packs2-0 and 2-1 has a data size of 2048 bytes, which matches the logicalsector information size. The video packs 1-0 to 1-3 and audio packs 2-0and 2-1 are abstractly handled as a plurality of pieces of logicalsector information 3-1 to 3-31 in the logical layer, as shown in (b) ofFIG. 1 (that is, examples of practical contents of the plurality ofpieces of logical sector information 3-1 to 3-31 correspond to videopacks 1-0 to 1-3 and audio packs 2-0 and 2-1). In method 1, sincephysical sector information and logical sector information match, thesepieces of information are handled as a plurality of pieces of physicalsector information 4-0 to 4-31, as shown in (c) of FIG. 1. As will bedescribed in detail later, each item of physical sector information (4-0to 4-31) has the following configuration. That is, 4-byte PIDinformation, 2-byte IED information, and a 10-byte reserve field (thesize in an existing DVD is 6 bytes) are arranged at the head of eachinformation, and a 4-byte EDC is arranged at the end of information(data 0-0-0 to data 0-0-5). After that, that sequence is broken up into188-byte data (each of the data 0-0-0 to data 0-0-5), error correctionPI (inner-code parity) data (PIO-0-0 to PI0-0-5) is appended to every188-byte data, and this data is arranged in turn, as shown in (d) ofFIG. 1. In odd-numbered physical sector data (physical sector data 5-0),PO (outer-code parity) data (POO) is arranged at the end of data tocomplete physical sector data 6-0. The present invention ischaracterized in that even-numbered physical sector data (physicalsector data 5-1) has a structure in which PO data (PO) is arranged inthe second column from the end of data, and data 1-1-5 and PI data(PI1-1-5) are arranged at the end of the even-numbered physical sectordata (as will be described in detail later). Physical sector data 5-0 to5-31, which is completed in this manner, is recorded on the physicalsector areas 9 a on the optical disk (information recording medium 9) inaccordance with the order it is arranged, as shown in (e) of FIG. 1. Onephysical sector data item is recorded on one physical sector area 9 a.

[0051] As shown in (f) and (g) of FIG. 2, one physical sector data 5-0item is formed as a combination of data in two different ECC blocks 8-0and 8-1. More specifically, data in the physical sector data 5-0 isfinely broken up into 200-byte data, and 188-byte data 0-0-0 and PI data0-0-0 are arranged in the first row in the ECC block 8-0. Next 188-bytedata 0-1-0 and PI 0-1-0 in the physical sector data 5-0 are arranged inthe first row in the ECC block 8-1. Furthermore, the next 188-byte data0-0-1 and PI data 0-0-1 are arranged in the second row in the ECC block8-0. Of PO data in the ECC block 8-1, the first 200 bytes are insertedin the sixth row in the ECC block 8-1 as PO0. As a result, data fromdata 0-0-0 to PO0 form the physical sector data 5-0.

[0052] First data 1-0-0 and PI 1-0-0 that follow the first data in thenext physical sector data 5-1 are arranged in the seventh row in the ECCblock 8-0, as shown in (f) of FIG. 2. Of PO data in the ECC block 8-0,the first 200-byte data is arranged as PO1 in the 12th row in the ECCblock 8-0. In this way, PO data (PO0, PO1) for respective rows (200bytes) is arranged at equal intervals for the respective physical sectordata 5-0 to 5-31, and the arrangement positions have a difference of onephysical sector data between a pair of ECC blocks 8-0 and 8-1.

[0053] The detailed structure in the ECC blocks 8-0 and 8-1 shown in (f)and (g) of FIG. 2 will be explained below with reference to FIG. 3.

[0054]FIG. 3 shows a combined state of two, right and left (for each200-byte column) ECC blocks. Each ETC block has a structure in which12-byte PI data is appended every 188 bytes, and PO data for 16 rows isappended. The PO data for 16 rows is decomposed into row data item, eachof which is interleaved and inserted at every 12-row positions. Thehatched portion of 200-byte columns per row in FIG. 3 means interleavedand inserted PO data.

[0055] The user information size assigned per sector is 2048 bytes as inan existing DVD, and information having the same contents as those oflogical sector information recognized in the application layer is set aseach item of physical sector information (main data). Four-byte data IDinformation, 2-byte IED information, and a 10-byte reserve field (thesize in an existing DVD is 6 bytes) are arranged at the head of 2048bytes of the physical sector information, and 4-byte EDC data isarranged at the end of the physical sector information, thus forming allthe data of a physical sector.

[0056] Since one physical sector data is interleaved across two smallECC blocks, an error-correctable burst error length can be improved tonearly twice that of the prior art. That is, one item of physical sectordata is broken up into 188-byte data items, each of which forms one rowdata by appending 12-byte PI data (since the existing PI size is 10bytes, and is increased to 12 bytes, error correction performance perrow can be improved), and this row data is alternately and sequentiallyarranged in right and left different ECC blocks. This embodiment ischaracterized in that data (data sector) in one physical sector has anodd number of rows, i.e., 11 rows, as shown in FIG. 3. Since the datasector is made up of an odd number of rows, the total number of rows canbe even upon inserting one PO row in each physical sector, and the POrow can be properly inserted in two ECC blocks without forming an oddrow.

[0057] PID information is always arranged at the head position (upperleft corner position in FIG. 3) of each physical sector, and the POinsert positions are devised to allow efficient interleave insertion ofPO data, as shown in FIG. 3. That is, PO data is arranged at the lastrow position of an even sector, and PO data is arranged at the secondrow position from the end of the sector in an odd sector. As a result,PO data is arranged in a single ECC block, and all physical sectors canhave the same data size.

[0058] An outline of method 2 will be explained below using FIGS. 4 and5.

[0059] As in method 1, AV information or stream information is stored inthe form of packs 1-0 to 1-3 and 2-0, as shown in (a) of FIG. 4, and theinformation contents of the packs 1-0 to 1-3 and 2-0 correspond to aplurality of pieces of logical sector information 3-0 to 3-16. For theplurality of pieces of logical sector information 3-0 to 3-16 obtainedat that time, ECC blocks 7-0 and 7-1 are formed and PI information(PI0-0-0 to PI16-1-1) and PO information (PO0-0, PO1-0) are inserted bythe same method as in the conventional DVD standards ((c) of FIG. 4).

[0060] A large characteristic feature of the present invention lies inthat processes from the state in (b) of FIG. 4 until (c) of FIG. 4,i.e., appending of data ID information, IED information, a reservefield, and EDC information and an insert process of PI information(PIO-0-0 to PI16-1-1) and PO information (PO0-0, P01-0) are the same asin those of the conventional DVD (the numbers of data byes are also thesame). Therefore, the structures in the ECC blocks 7-0 and 7-1 shown in(f) and (g) of FIG. 5 perfectly match the conventional DVD standards aswell as the values of various numbers of data byes. As a result, some ofthe ECC block generation process (generation of PI and PO, and the like)and error correction process in a reproduction apparatus orrecording/reproduction apparatus having compatible functions between theexisting DVD and next-generation DVD can be used in common to those uponusing an existing DVD disk (medium), and the processing routines andcircuits of the reproduction apparatus or recording/reproductionapparatus having compatible functions between the existing DVD andnext-generation DVD can be simplified.

[0061] In order to improve an error-correctable burst error length byinterleaving data in physical sector data 5-0 and 5-16 between the twoECC blocks 7-0 and 7-1, method 2 of the present invention executes anexchange process between data rows and PI rows (data 0-0-1 and PI0-0-1,and data 16-1-1 and PI16-1-1) located at the even-numbered row positionsof logical sector data at identical positions (having the same rownumbers) in the neighboring ECC blocks 7-0 and 7-1, as shown in (d) ofFIG. 4. Data ID information that contains sector address information isarranged in the first row in each logical sector data. Hence, when onlyan exchange process between data rows and PI rows at the even-numberedrow positions is done, and an exchange process between data rows and PIrows at odd-numbered row positions is inhibited, arrangement of the dataID information that contains sector address information at the headpositions in the physical sector data 5-0 and 5-16 shown in (d) of FIG.4 is guaranteed. Each of the logical sector data items 6-0 and 6-16always includes 12 rows (an even number of rows) of data and PI rows.Hence, by exchanging data and PI rows at the even-numbered row positionsin the logical sector data items 6-0 and 6-16 according to theaforementioned rules, the positions of PO information (PO0-0, PO1-0) inthe logical sector data items 6-0 and 6-1 and ECC blocks 7-0 and 7-1remain unchanged without being exchanged. For this reason, the appendingprocess of PO information and error correction process are facilitated.The physical sector data items 5-0 and 5-16 generated in this way arerecorded on the physical sector areas 9 a on an optical disk(information recording medium 9) in accordance with the order data inthe physical sector data items 5-0 and 5-16 are arranged. One physicalsector data is recorded on one physical sector area 9 a.

[0062] An example of an information recording/reproduction apparatus(information recording apparatus or information reproduction apparatus)will be explained below using FIG. 6.

[0063] 1. Function of Information Recording/Reproduction Apparatus

[0064] 1-1. Basic Function of Information Recording/ReproductionApparatus

[0065] An information recording/reproduction apparatus executes thefollowing processes. That is,

[0066] the apparatus records new information or rewrites (or erases)information at a predetermined position on the information recordingmedium 9 using a focused beam spot; and

[0067] the apparatus reproduces already recorded information from apredetermined position on the information recording medium 9 using afocused beam spot.

[0068] 1-1-1. Basic Function Achieving Means of InformationRecording/Reproduction Apparatus

[0069] As means for achieving the above basic functions, the informationrecording/reproduction apparatus executes the following processes. Thatis,

[0070] the apparatus traces a focused beam spot along tracks (not shown)on the information recording medium 9;

[0071] the apparatus switches recording/reproduction/ erasure ofinformation by changing the amount of light of a focused beam spot withwhich the information recording medium 9 is irradiated; and

[0072] the apparatus converts an externally input recording signal dinto an optimal signal to record it at high density and with a low errorrate.

[0073] 2. Structure of Mechanism Portion and Operation of DetectionPortion

[0074] 2-1. Basic Structure of Optical Head 202 and Signal DetectionCircuit

[0075] 2-1-1. Signal Detection by Optical Head 202

[0076] The optical head 202 basically comprises a semiconductor laserelement as a light source, a photodetector, and an objective lens. Alaser beam emitted by the semiconductor laser element is focused on theinformation recording medium 9 via the objective lens. The laser beamreflected by a light reflection film or light reflective recording filmof the information recording medium 9 is photoelectrically converted bythe photodetector. A detection current obtained by the photodetectorundergoes current-voltage conversion by an amplifier 213 to obtain adetection signal. This detection signal is processed by afocusing/tracking error detection circuit 217 or binarization circuit212. In general, the photodetector is divided into a plurality ofphotodetection regions, which individually detect changes in the amountof light with which the respective photodetection regions areirradiated. Respective detection signals undergo sum/differencecalculations by the focusing/tracking error detection circuit 217, thusdetecting focusing and tracking errors. In this way, a change in theamount of light reflected by the light reflection film or lightreflective recording film of the information recording medium 9 isdetected, thereby reproducing a signal on the information recordingmedium 9.

[0077] 2-1-2. Objective Lens Actuator Structure

[0078] The objective lens that focuses a laser beam emitted by thesemiconductor laser element on the information recording medium 9 ismovable in two axis directions in accordance with an output current froman objective lens actuator driving circuit 218. The objective lensmoves:

[0079] in a direction perpendicular to the information recording medium9 to correct focusing errors; and

[0080] in the radial direction of the information recording medium 9 tocorrect tracking errors.

[0081] Such an objective lens moving mechanism is called an objectivelens actuator (not shown).

[0082] 2-2. Rotation Control System of Information Recording Medium 9

[0083] The information recording medium 9 is mounted on a rotary table221 which is rotated by the driving force of a spindle motor 204. Therotational speed of the information recording medium 9 is detected basedon a reproduction signal obtained from the information recording medium9. That is, the detection signal (analog signal) output from theamplifier 213 is converted into a digital signal by the binarizationcircuit 212, and a PLL circuit 211 generates a constant period signal(reference clock signal) based on that digital signal. An informationrecording medium rotational speed detection circuit 214 detects therotational speed of the information recording medium 9 using thissignal, and outputs the detection value.

[0084] A correspondence table of the information recording mediumrotational speed which corresponds to the radial position where data isreproduced or recorded/erased on the information recording medium 9 ispre-stored in a semiconductor memory 219. When a reproduction positionor recording/erasure position is determined, a controller 220 sets atarget rotational speed of the information recording medium 9 by lookingup information recorded in the semiconductor memory 219, and sends thatvalue to a spindle motor driving circuit 215.

[0085] The spindle motor driving circuit 215 calculates the differencebetween this target rotational speed and the output signal (currentrotational speed) of the information recording medium rotational speeddetection circuit 214, and supplies the driving current corresponding tothat difference to the spindle motor 204, thus controlling therotational speed of the spindle motor 204 to be constant. The outputsignal from the information recording medium rotational speed detectioncircuit 214 is a pulse signal having a frequency corresponding to therotational speed of the information recording medium 9, and the spindlemotor driving circuit 215 controls both the frequency and pulse phase ofthis signal.

[0086] 2-3. Optical Head Moving Mechanism

[0087] To move the optical head 202 in the radial direction of theinformation recording medium 9, an optical head moving mechanism (feedmotor) 203 is provided.

[0088] 3. Functions of Respective Control Circuits

[0089] 3-1. Focused Beam Spot Trace Control

[0090] In order to perform focusing or tracking error correction, acircuit for supplying a driving current to the objective lens actuatorin the optical head 202 in accordance with the output signal (detectionsignal) from the focusing/tracking error detection circuit 217 is theobjective lens actuator driving circuit 218. This circuit 218 includes aphase compensation circuit for improving characteristics incorrespondence with the frequency characteristics of the objective lensactuator to attain quick response of objective lens movement up to thehigh-frequency range.

[0091] In response to a command from the controller 220, the objectivelens actuator driving circuit 218 executes:

[0092] an ON/OFF process of focusing/tracking error correction operation(focus/track loop);

[0093] a process for moving the objective lens at low speed in adirection (focus direction) perpendicular to the information recordingmedium 9 (executed when focus/track loop is OFF); and

[0094] a process for moving a focused beam spot to a neighboring trackby slightly moving in the radial direction (direction to cross tracks)of the information recording medium 9 using a kick pulse.

[0095] 4. Various Operations Associated with Control System of MechanismPortion

[0096] 4-1. Startup Control

[0097] When the information recording medium 9 is mounted on the rotarytable 221 and startup control is started, the processes are executed inaccordance with the following sequence.

[0098] 1) The controller 220 sends a target rotational speed to thespindle motor driving circuit 215, which supplies a driving current tothe spindle motor 204, thus starting rotation of the spindle motor 204.

[0099] 2) At the same time, the controller 220 issues a command(execution command) to the feed motor driving circuit 216, whichsupplies a driving current to the optical head driving mechanism (feedmotor) 203, thus moving the optical head 202 to the innermost peripheralposition of the information recording medium 9. It is confirmed if theoptical head 202 has reached an inner peripheral portion beyond theinformation recording region on the information recording medium 9.

[0100] 3) When the spindle motor 204 has reached the target rotationalspeed, that status (status report) is output to the controller 220.

[0101] 4) A semiconductor laser driving circuit 205 supplies a currentto the semiconductor laser element in the optical head 202 incorrespondence with a reproduction light amount signal sent from thecontroller 220 to a recording/reproduction/erasure control waveformgeneration circuit 206, thus starting laser emission.

[0102] Note that an optimal irradiation light amount upon reproductionvaries depending on the types of information recording media 9. Uponstartup, the lowest irradiation light amount value of those values isset.

[0103] 5) The objective lens actuator driving circuit 218 controls tomove the objective lens (not shown) in the optical head 202 to aposition farthest from the information recording medium 9, and make theobjective lens slowly approach the information recording medium 9 inaccordance with a command from the controller 220.

[0104] 6) At the same time, the focusing/tracking error detectioncircuit 217 monitors a focusing error amount, and outputs status to thecontroller 220 when the objective lens has approached an in-focusposition.

[0105] 7) Upon receiving that status, the controller 220 issues acommand to the objective lens actuator driving circuit 218 to enable thefocus loop.

[0106] 8) The controller 220 issues a command to the feed motor drivingcircuit 216 while the focus loop is ON to slowly move the optical head202 toward the outer periphery of the information recording medium 9.

[0107] 9) At the same time, a reproduction signal from the optical head202 is monitored. When the optical head 202 has reached the recordingregion on the information recording medium 9, the controller 220 stopsmovement of the optical head 202, and issues a command to the objectivelens actuator driving circuit 218 to enable the track loop.

[0108] 10) An “optimal light amount upon reproduction” and “optimallight amount upon recording/erasure” recorded on the inner peripheralportion of the information recording medium 9 are reproduced, and arerecorded in the semiconductor memory 219 via the controller 220.

[0109] 11) Furthermore, the controller 220 sends a signal correspondingto that “optimal light amount upon reproduction” to therecording/reproduction/erasure control waveform generation circuit 206,thus re-setting the emission amount of the semiconductor laser elementupon reproduction.

[0110] 12) The emission amount of the semiconductor laser element uponrecording/erasure is set in correspondence with the “optimal lightamount upon recording/erasure” recorded on the information recordingmedium 9.

[0111] 4-2. Access Control

[0112] 4-2-1. Reproduction of Access Destination Information oninformation recording medium 9

[0113] Information that indicates the locations and contents ofinformation recorded on the information recording medium 9 variesdepending on the types of information recording medium 9, and isgenerally recorded in directory management regions, navigation packs, orthe like in the information recording medium 9. Note that the directorymanagement regions are recorded together in the inner or outerperipheral region of the information recording medium 9. On the otherhand, the navigation pack is contained in a VOBS (Video Object Set)complying with the data structure of a PS (Program Stream) of MPEG2, andrecords information indicating the location of the next video data.

[0114] When specific information is to be reproduced or recorded/erased,information in the above-mentioned region is reproduced, and an accessdestination is determined based on the reproduced information.

[0115] 4-2-2. Coarse Access Control

[0116] The controller 220 calculates the radial position of the accessdestination, and detects the distance between that position and thecurrent position of the optical head 202. As for the moving distance ofthe optical head 202, velocity curve information that allows the head toreach the target position within a shortest period of time is stored inadvance in the semiconductor memory 219. The controller 220 reads thatinformation, and controls movement of the optical head 202 by thefollowing method in accordance with the velocity curve. The controller220 issues a command to the objective lens actuator driving circuit 218to disable the track loop, and then controls the feed motor drivingcircuit 216 to start movement of the optical head 202. When the focusedbeam spot has crossed a track on the information recording medium 9, thefocusing/tracking error detection circuit 217 generates a tracking errordetection signal. Using this tracking error detection signal, therelative velocity of the focused beam spot with respect to theinformation recording medium 9 can be detected. The feed motor drivingcircuit 216 calculates the difference between the relative velocity ofthe focused beam spot obtained from the focusing/tracking errordetection circuit 217, and target velocity information sent from thecontroller 220, and feeds back that result to the driving current to besupplied to the optical head driving mechanism (feed motor) 203, thusmoving the optical head 202. As described in “optical head movingmechanism”, a frictional force always acts between a guide shaft andbushing or bearing. When the optical head 202 moves at high speed,dynamic friction acts. However, since the moving velocity of the opticalhead 202 is low at the beginning of movement and immediately beforestop, static friction acts. At that time, since the relative frictionalforce increases, the amplification factor (gain) of a current to besupplied to the optical head driving mechanism (feed motor) 203 isincreased in response to a command from the controller 220 (especially,immediately before stop).

[0117] 4-2-3. Fine Access Control

[0118] When the optical head 202 has reached the target position, thecontroller 220 issues a command to the objective lens actuator drivingcircuit 218 to enable the track loop. The focused beam spot reproducesan address or track number of that portion while tracing along a trackon the information recording medium 9. The current focused beam spotposition is detected from that address or track number, and thecontroller 220 calculates the number of error tracks from the reachedtarget position and informs the objective lens actuator driving circuit218 of the number of tracks the focused beam spot is required to move.When the objective lens actuator driving circuit 218 generates a pair ofkick pulses, the objective lens slightly moves in the radial directionof the information recording medium 9, thus moving the focused beam spotto a neighboring track. In the objective lens actuator driving circuit218, the track loop is temporarily disabled, and after kick pulses aregenerated a given number of times corresponding to the information fromthe controller 220, the track loop is enabled again. Upon completion offine access, the controller 220 reproduces information (address or tracknumber) at the position where the focused beam spot is tracing, andconfirms if it has accessed a target track.

[0119] 4-3. Continuous Recording/Reproduction/Erasure Control

[0120] As shown in FIG. 6, a tracking error detection signal output fromthe focusing/tracking error detection circuit 217 is input to the feedmotor driving circuit 216. “Upon startup control” and “upon accesscontrol” mentioned above, the controller 220 controls the feed motordriving circuit 216 not to use the tracking error detection signal.After it is confirmed that the focused beam spot has reached the targettrack by access, some components of the tracking error detection signalare supplied as a driving current to the optical head driving mechanism(feed motor) 203 in response to a command from the controller 220. Thiscontrol continues during the period in which a reproduction orrecording/erasure process is done continuously. The informationrecording medium 9 is mounted so that its central position has a slighteccentricity from that of the rotary table 221. When some components ofthe tracking error detection signal are supplied as a driving current,the entire optical head 202 slightly moves in correspondence with theeccentricity. When the reproduction or recording/ erasure process iscontinuously done for a long period of time, the focused beam spotposition gradually moves toward the outer or inner periphery. When somecomponents of the tracking error detection signal are supplied as adriving current to the optical head moving mechanism (feed motor) 203,the optical head 202 gradually moves toward the outer or inner peripheryin correspondence with that current. In this manner, the load ontracking error correction of the objective lens actuator is reduced,thus attaining a stable track loop.

[0121] 4-4. End Control

[0122] When a series of processes are complete and the operation is tobe ended, the process is done in accordance with the following sequence.That is,

[0123] 1) the controller 220 issues a command to the objective lensactuator driving circuit 218 to disable the track loop;

[0124] 2) the controller 220 issues a command to the objective lensactuator driving circuit 218 to disable the focus loop;

[0125] 3) the controller 220 issues a command to therecording/reproduction/erasure control waveform generation circuit 206to stop emission of the semiconductor laser element; and

[0126] 4) the controller 220 informs the spindle motor driving circuit215 of zero reference rotational speed.

[0127] 5. Flow of Recording Signal/Reproduction Signal to InformationRecording Medium

[0128] 5-1. Signal Format Recorded on Information Recording Medium 9

[0129] In order to meet requirements:

[0130] of correcting recording information errors caused by defects onthe information recording medium 9;

[0131] of simplifying a reproduction processing circuit by setting zeroDC components of a reproduction signal; and

[0132] of recording information at highest possible density on theinformation recording medium 9 for a signal to be recorded on theinformation recording medium 9, the information recording/reproductionapparatus (physical system block) performs “addition of an errorcorrection function” and “signal conversion of recording information(signal modulation/ demodulation)”, as shown in FIG. 6.

[0133] 5-2. Flow of Signal Upon Recording

[0134] 5-2-1. ECC (Error Correction Code) Appending Process

[0135] Information to be recorded on the information recording medium 9is input to a data input/output interface 222 as recording signal d inthe form of a raw signal. This recording signal d is directly recordedin the semiconductor memory 219, and then undergoes an ECC appendingprocess in an ECC encoding circuit 208, as will be described later.

[0136] Upon completion of appending of inner-code PI and outer-code PO,the ECC encoding circuit 208 reads data for one sector from thesemiconductor memory 219, and transfers the read data to a modulationcircuit 207.

[0137] 5-2-2. Signal Modulation

[0138] In order to make a DC component (DSV: Digital Sum Value) of areproduction signal approach zero, and to record information on theinformation recording medium 9 at high density, signal modulation asconversion of a signal format is done in the modulation circuit 207. Themodulation circuit 207 and a demodulation circuit 210 include aconversion table indicating the relationship between a source signal andmodulated signal. The signal transferred from the ECC encoding circuit208 is segmented into data each consisting of a plurality of bits inaccordance with a modulation scheme, and the segmented data is convertedinto other signals (codes) by looking up the conversion table. Forexample, when {fraction (8/16)} modulation (RLL (2, 10) code) is used asthe modulation scheme, two different types of conversion tables arepresent, and the conversion table to be looked up is switched as neededto make the DC component (DSV) after modulation approach zero.

[0139] 5-3. Flow of Signal Upon Reproduction

[0140] 5-3-1. Binarization/PLL Circuit

[0141] As described in “signal detection by optical head 202”, a changein the amount of light reflected by the light reflection film or lightreflective recording film of the information recording medium 9 isdetected to reproduce a signal on the information recording medium 9. Asignal obtained by the amplifier 213 has an analog waveform. Thebinarization circuit 212 converts that signal into a binary digitalsignal consisting of “1” and “0” using a comparator.

[0142] From the reproduction signal obtained by the binarizationcircuit, the PLL circuit 211 extracts a reference signal uponreproducing information. The PLL circuit 211 incorporates a variablefrequency oscillator. The frequency and phase of a pulse signal(reference clock) output from the oscillator are compared with those ofthe output signal from the binarization circuit 212, and the comparisonresults are fed back to the oscillator output.

[0143] 5-3-2. Signal Demodulation

[0144] The demodulation circuit 210 incorporates a conversion tableindicating the relationship between modulated and demodulated signals. Amodulated signal is restored to an original signal by looking up theconversion table in synchronism with the reference clock obtained by thePLL circuit 211. The restored (demodulated) signal is recorded in thesemiconductor memory 219.

[0145] 5-3-3. Error Correction Process

[0146] An error correction circuit 209 detects any errors of a signalsaved in the semiconductor memory 219 using inner-code PI and outer-codePO, and sets pointer flags of error positions.

[0147] After that, the error correction circuit 209 corrects a signal atthe error positions in accordance with the error pointer flags whilereading out the signal from the semiconductor memory 219, removesinner-code PI and outer-code PO, and transfers the signal to the datainput/output interface 222.

[0148] A signal sent from the ECC encoding circuit 208 is output asreproduction signal c from the data input/output interface 222.

[0149] This concludes the detailed description of FIG. 6 is to end.

[0150] The format process sequence executed in the apparatus shown inFIG. 6 will be explained below using the flowchart shown in FIG. 7. Theformat process is implemented by the ECC encoding circuit 208 andcontroller 220. FIG. 7 shows the sequence of the data conversion process(format) based on method 1 shown in FIGS. 1 to 3.

[0151] Step 1) A plurality of pieces of physical sector information 4-0to 4-31 are set (segmented into main data in units of 2048 bytes) incorrespondence with the size of a plurality of pieces of logical sectorinformation 3-0 to 3-31. User data to be recorded is handled in units of2048 bytes.

[0152] Step 2) 2068-byte sector data is generated from 2048-byte maindata, 16-byte auxiliary data, and a 4-byte error detection code (EDC).

[0153] As shown in FIG. 8, the 16-byte auxiliary data contains 4-bytedata ID data (PID), a 2-byte error detection code (IED) for the data ID,and 10-byte reserve data (RSV). The PID records a sector number used toidentify a data sector, and sector information used to identify thecontents of the data sector. The IED is used to detect any errorsgenerated in the PID portion. The RSV is used to record other kinds ofauxiliary information (e.g., copyright management information). The EDCis used to detect any errors generated in 2064-byte main data andauxiliary data. The data sectors are arranged in a 188 (columns)×11(rows) matrix, as shown in FIG. 8.

[0154] Step 3) Scramble data is added to 2048-byte main data of eachsector data.

[0155] Step 4) The rows of the sector data shown in FIG. 8 arere-arranged depending on whether the sector number is even or odd, asshown in FIG. 9. Numerals in FIG. 9 indicate row numbers in the sectordata. Also, as shown in FIG. 9, re-arrangement types α and β areavailable.

[0156] Step 5) A sector block is generated by vertically stacking 32continuous data sectors, which are re-arranged depending on their sectornumbers. The data sectors which are vertically stacked are arranged in a376 (columns) x 176 (rows) matrix, as shown in FIG. 10.

[0157] Step 6) The sector block is horizontally segmented into twoblocks to encode error correction codes. The 188 (columns)×176 (rows)blocks after segmentation undergo encoding in the column direction togenerate outer-code parity (PO) data for 16 rows. The outer code uses aREED Solomon code of RS(192, 176, 17). Subsequently, inner-code encodingis done in the row direction to generate inner-code parity data (PI) for12 columns. The inner code uses a REED Solomon code of RS (200, 188,13). ECC blocks containing parity data generated based on the inner andouter codes are as shown in FIG. 11.

[0158] Step 7) The ECC blocks undergo row interleave to distribute 16right and left rows of PO data into the blocks. Thirty-two rows (=16×2)of PO data are distributed row by row to sectors. At this time, PO rowsof the left block are inserted after the lowermost row of only five oddrows, and PO rows of the right block are inserted after the lowermostrow of only five even rows. FIG. 3 shows the ECC blocks after rowinterleave.

[0159] Step 8) Physical sector data is completed. FIG. 12 shows thecompleted physical sector data (=physical sector data blocks).

[0160] Step 9) A zigzag recording matrix is set.

[0161] Step 10) A modulation process is executed. If a bit sequence ofdata to be recorded is directly recorded on the medium, thecharacteristic feature of the recording data sequence does not match therecording characteristics of the medium, and efficient recording cannotbe done. In consideration of the recording characteristics of themedium, a data pattern is converted according to a predeterminedconversion rule. For example, the modulation scheme includes an 8/16modulation scheme for converting 1-byte data into a 16-bit pattern, an8/12 modulation scheme for converting 1-byte data into a 1.5-bytepattern, a 12/18 modulation scheme for converting 12-bit data into an18-bit pattern, and the like. Any one of these schemes comprises aplurality of conversion tables and a logic circuit for selecting theconversion table.

[0162] Especially, since the 12/18 modulation scheme that converts1.5-byte data has a characteristic of expanding an error at one positionto 1.5 bytes, it is effective for the process executed in step 9 todistribute errors upon reproduction.

[0163] Via steps 1 to 10, zigzag recording according to the setup instep 9 is done. Zigzag recording will be described in detail below. Thecontents of the physical sector data structure shown in FIG. 12 aresegmented further finely. Assume that the fine segmentation size is 1byte, as shown in, e.g., FIG. 13. However, the present invention is notlimited to such specific segmentation unit length, and for example, a 2-or 4-byte unit may be used. Data are selected and extracted across rowsfor respective segmentation units, and are recorded on the physicalsector area 9 a on the optical disk (information recording medium 9) inaccordance with the order they are selected and extracted. One physicalsector data is recorded on one physical sector area 9 a.

[0164] For example, as shown in FIG. 13, two upper and lower rows arepaired, data in these upper and lower rows is extracted alternately (ina zigzag pattern) for respective segmentation units, and upon completionof one cycle of data extraction in a single column, unextracted data inthese pairs of rows is alternately fetched and recorded on the physicalsector area 9 a on the optical disk (information recording medium 9).

[0165] In this case, the format method for method 1 has been mainlyexplained. However, the process in step 9 is also effective for method2. Especially, in method 2, since neighboring rows belong to thedifferent ECC blocks 7-0 and 7-1, as shown in FIGS. 4 and 5, if data isarranged across rows, data distribution across the ECC blocks 7-0 and7-1 is attained. Hence, error distribution can be attained at a levelfiner than the interleave process across the ECC blocks 7-0 and 7-1 forrespective rows.

[0166] In FIG. 13, data is extracted in a zigzag pattern from a pair ofrows. However, the present invention is not limited to this. Forexample, data may be sequentially extracted across three rows, or datamay be selected and extracted for respective segmentation units acrossall six rows, and may be re-arranged and recorded on the physical sectorarea 9 a on the optical disk (information recording medium 9).

[0167] As another recording method, data of different ECC blocks everyrows may be alternately recorded for several bytes, e.g., 1 byte.

[0168] Also, recording of data for one row in an order it is arrangeddoes not disturb the basic feature of the present invention.

[0169] Furthermore, a physical sector information portion may bere-arranged in any stage before step 6 so that auxiliary informationcontaining at least an ID continuously appears on a recorded datasequence in accordance with the data recording order in step 9.

[0170] The information recording medium on which physical sector data isrecorded in this way is reproduced by the informationrecording/reproduction apparatus shown in FIG. 6. That is, physicalsector data is read out from a predetermined number of (32) physicalsector areas 9 a, n (2) ECC blocks are generated from the readoutphysical sector data, sector data is generated and reproduced from theECC blocks via an error correction process. The physical sector data isread out by the optical head. The sector data is reproduced by the errorcorrection circuit 209.

[0171] More specifically, by utilizing a process opposite to that forgenerating a predetermined number of physical sector data from n ECCblocks, n ECC blocks are generated from the predetermined number ofphysical sector data items read out from the predetermined number ofphysical sector areas 9 a. That is, two ECC blocks shown in FIG. 3 aregenerated from the physical sector data shown in FIG. 12. Subsequently,by utilizing a process opposite to that for generating ECC blocks afterrow interleave from those before row interleave, the n generated ECCblocks are restored to n ECC blocks before row interleave. That is, n(2) ECC blocks shown in FIG. 3 are restored to n ECC blocks shown inFIG. 11. At this time, an error correction process is executed usingouter- and inner-code parity data appended to the ECC blocks. Byutilizing a process opposite to that for generating ECC blocks fromsector blocks, the ECC blocks are restored to sector blocks. That is,outer- and inner-code parity data is removed from the ECC blocks shownin FIG. 11 to generate sector blocks shown in FIG. 10. Then, byutilizing a process opposite to that for generating sector blocks fromsector data, sector data is generated from the sector blocks. That is,sector data shown in FIG. 9 is generated from the sector blocks shown inFIG. 10. Since the generated sector data is in the re-arranged state, itis restored to an original arrangement upon reproduction.

[0172] Note that the physical sector data has a data structure in whichthe data ID is arranged at the head of the data, and a data line formedby only a portion of outer-code parity data is arranged as the finalline. Hence, the information recording/reproduction apparatus shown inFIG. 6 can reproduce the data ID by reading out the head data of thephysical sector data. Each physical sector area records data alternatelyextracted from different data lines in the physical sector data in turn(zigzag recording). Hence, the information recording/reproductionapparatus reproduces each physical sector area under the condition thatdata alternately extracted from different data lines is recorded.

[0173]FIG. 14 shows another embodiment of the data structure in physicalsector data in method 1. As shown in FIG. 14, data structures (A) to (C)are available, and are application examples which can be basicallygenerated via the aforementioned steps.

[0174] The format process for case (C) in FIG. 14, i.e., a case whereinone sector is formed of an even number of rows, will be explained belowusing the flowchart shown in FIG. 7 again.

[0175] The process to be described below is executed in the ECC encodingcircuit 208 shown in FIG. 6, and detailed control is made by thecontroller 220.

[0176] Step 1) A plurality of pieces of physical sector information 4-0to 4-31 are set (segmented into main data in units of 2048 bytes) incorrespondence with the size of a plurality of pieces of logical sectorinformation 3-0 to 3-31. User data to be recorded is handled in units of2048 bytes.

[0177] Step 2) 2064-byte sector data is generated from 2048-byte maindata, 12-byte auxiliary data, and a 4-byte error detection code (EDC).As shown in FIG. 16, the 12-byte auxiliary data contains 4-byte data IDdata (PID), a 2-byte error detection code (IED) for the data ID, and6-byte reserve data (RSV). The sector data is arranged in a 172(columns)×12 (rows) matrix, as shown in FIG. 16.

[0178] Step 3) Scramble data is added to 2048-byte main data of eachsector data.

[0179] Step 4) The rows of the sector data shown in FIG. 16 arere-arranged depending on whether the sector number is even or odd, asshown in FIG. 17. Numerals in FIG. 17 indicate row numbers in the sectordata. Also, as shown in FIG. 17, re-arrangement types α and β areavailable.

[0180] Step 5) A sector block is generated by vertically stacking 32continuous data sectors, which are re-arranged depending on their sectornumbers. The sectors are which are vertically stacked are arranged in a344 (columns)×192 (rows) matrix, as shown in FIG. 18.

[0181] Step 6) The sector block is horizontally segmented into twoblocks to encode error correction codes. The 172 (columns)×192 (rows)blocks after segmentation undergo encoding in the column direction togenerate outer-code parity (PO) data for 16 rows. The outer code uses aREED Solomon code of RS(208, 192, 17). Subsequently, inner-code encodingis done in the row direction to generate inner-code parity data (PI) for12 columns. The inner code uses a REED Solomon code of RS(184, 172, 13).ECC blocks containing parity data generated based on the inner and outercodes are as shown in FIG. 19.

[0182] Step 7) The ECC blocks undergo row interleave to distribute 16right and left rows of PO data into the blocks. Thirty-two rows (=16×2)of PO data are distributed row by row to sectors. As the distributiondestinations of PO data, this data is inserted after the lowermost rowof even sectors in the left block, and after the lowermost row of oddsectors in the right block. FIG. 15 shows the ECC blocks after rowinterleave.

[0183] Step 8) Physical sector data is completed. FIG. 20 shows thecompleted physical sector data.

[0184] Step 9) In this case, the setup of the zigzag recording matrix isomitted. This is because two different physical sector data items areinvolved at the lowermost row of the physical sector data (see FIG. 15).If the zigzag recording matrix is set in this case, two differentphysical sectors are mixed together in one physical sector area.

[0185] Step 10) A modulation process is executed. If a bit sequence ofdata to be recorded is directly recorded on the medium, thecharacteristic feature of the recording data sequence does not match therecording characteristics of the medium, and efficient recording cannotbe done. In consideration of the recording characteristics of themedium, a data pattern is converted according to a predeterminedconversion rule.

[0186] The information recording medium on which physical sector data isrecorded in this way is reproduced by the informationrecording/reproduction apparatus shown in FIG. 6. That is, physicalsector data is read out from a predetermined number of (32) physicalsector areas 9 a, n (2) ECC blocks are generated from the readoutphysical sector data, sector data is generated and reproduced from theECC blocks via an error correction process.

[0187] More specifically, by utilizing a process opposite to that forgenerating a predetermined number of physical sector data items from nECC blocks, n ECC blocks are generated from the predetermined number ofphysical sector data items read out from the predetermined number ofphysical sector areas 9 a. That is, two ECC blocks shown in FIG. 15 aregenerated from the physical sector data shown in FIG. 20. Subsequently,by utilizing a process opposite to that for generating ECC blocks afterrow interleave from those before row interleave, the n generated ECCblocks are restored to n ECC blocks before row interleave. That is, n(2) ECC blocks shown in FIG. 15 are restored to n ECC blocks shown inFIG. 19. At this time, an error correction process is executed usingouter- and inner-code parity data appended to the ECC blocks. Byutilizing a process opposite to that for generating ECC blocks fromsector blocks, the ECC blocks are restored to sector blocks. That is,outer- and inner-code parity data is removed from the ECC blocks shownin FIG. 19 to generate sector blocks shown in FIG. 18. Then, byutilizing a process opposite to that for generating sector blocks fromsector data, sector data is generated from the sector blocks. That is,sector data shown in FIG. 17 is generated from the sector blocks shownin FIG. 18. Since the generated sector data is in the re-arranged state,it is restored to an original arrangement upon reproduction.

[0188] Note that the physical sector data has a data structure in whichthe data ID is arranged at the head of the data, and a data line formedby only a portion of outer-code parity data is arranged as the finalline. Hence, the information recording/reproduction apparatus shown inFIG. 6 can reproduce the data ID by reading out the head data of thephysical sector data.

[0189] Points of the present invention described above will besummarized below.

[0190] (1) One physical sector is segmented into rows including PI, androw data is assigned to a plurality of ECC blocks.

[0191] (2) In the data arrangement of all physical sectors, the data IDis always arranged at the head position. This structure matches the dataarrangement in physical sectors of the existing DVD. In this manner,since the data arrangement in an important portion in each physicalsector matches that of the existing DVD standards, the access controland sector address detection/confirmation processes in a reproductionapparatus or recording/reproduction apparatus having compatiblefunctions between the existing DVD and next-generation DVD can becommonly used, thus simplifying control in the apparatus.

[0192] (3) All physical sectors have equal sizes.

[0193] (4) “2 ECC blocks=32 physical sectors” is set as a basic unit incorrespondence with the SOBU size, and all data in 32 physical sectorsis assigned to two ECC blocks in the basic unit.

[0194] (5) Physical sector information matches logical sectorinformation. The contents of one physical sector data are segmented intorows each including PI data, row data is assigned in turn to n (n≧2) ECCblocks, and the total of the number of rows each including PI in onephysical sector data and the number of PO rows is an integer multiple ofn.

[0195] (6) All pieces of information in one logical sector are containedin data in a single ECC block.

[0196] (7) Data in rows assigned to different ECC blocks in a singlephysical sector is selected in turn and is recorded on the optical disk.

[0197] The arrangements and effects of the information recording medium,information recording apparatus, and information reproduction apparatusof the present invention will be described in detail below.

[0198] <1>First to Fifth Data Units are Defined as Follows.

[0199] A minimum unit recorded on a medium from which information can bereproduced or on which information can be recorded is defined as a firstdata unit (physical sector). A second data unit (a group of n ECCblocks) including the first data unit is defined. A third data unit (ECCblock data) which is included in the second data unit and forms an ECCblock that forms a REED Solomon product code is defined. The second dataunit includes n (n is a positive number equal to or greater than 2)independent third data units having equal data sizes. A fourth data unitwhich is included in the third data unit and forms one row as a dataarrangement appended with PI (inner-code parity) data is defined. Afifth data unit (PO for one row) which forms PO (outer-code parity) datain the third data unit and is segmented to be equal to the size (rowsize) of the fourth data unit is defined.

[0200] The first data unit is formed by a set of fourth and fifth dataunits, the total of the number of fourth data units (the number of rowscontaining PI) and the number of fifth data units (the number of POrows) is an integer multiple of n, and a data structure in which data ofthe fourth data units is always arranged at specific positions in thefirst data unit and a data ID containing address information is alwaysarranged at a specific position in the fourth data unit is generated.

[0201] The information recording medium of the present inventioncomprises a physical sector area on which data with the aforementioneddata structure is recorded. The information recording apparatus andmethod of the present invention generate data with such a datastructure, and record the data with the data structure on theinformation recording medium. Furthermore, the information reproductionapparatus and method of the present invention reproduce the informationrecording medium on which the data with such a data structure isrecorded.

[0202] The relationship between the aforementioned data units is asfollows. second data unit ⊃ first data unit ⊃ fourth data unit (n × ECCblock) (physical sector) (row including PI) second data unit ⊃ Thirddata unit ⊃ fourth data unit (n × ECC block) (ECC block) (row includingPI) second data unit ⊃ Third data unit ⊃ fifth data unit (n × ECC block)(ECC block) (row including PO)

[0203] The points of the present invention are as follows.

[0204] 1) Data in one physical sector is segmented into rows, and rowdata is assigned to a plurality of ECC blocks.

[0205] 2) A data ID is arranged at the head position in the physicalsector, and PO data for one row is arranged in a row other than thefirst row.

[0206] 3) The sum of the number of rows including PI and the number ofPO rows is an integer multiple of the number of corresponding ECCblocks.

[0207] The effects of the present invention are as follows.

[0208] 1) Since the physical sector information size is the same as thatin the existing DVD (2048 bytes), full compatibility between thestandard contents of the logical layer and application layer of theexisting DVD can be assured, and existing DVD data can be effectivelyused by exchange and mixed storage of data recorded on existing DVDs ispossible.

[0209] 2) Since n third data units are included in the second data unit,and physical sector data (first data unit) is interleaved and arrangedin different ECC blocks (third data units) for respective rows (fourthdata units), an error-correctable burst error length can be improvedapproximately to n times. Hence, the present invention can relativelyeasily improve the error-correctable burst error length greatly withoutconsiderably lowering the main data information encoding efficiencycompared to the existing DVD standards.

[0210] 3) The effect of a perfect product code formed by appendinginner-code (PI) data in the horizontal direction and outer-code (PO)data in the vertical direction is as follows.

[0211] Since inner-code correction for outer-code parity data andouter-code correction for inner-code parity data can be done, correctionperformance can be improved by repeating correction using inner andouter code data for all recorded data.

[0212] In combination with recording interleave, both distribution ofsuccessive errors to inner-code data and perfection of a product codethat allows repetitive correction can be achieved.

[0213] Upon examining a method of “appending inner-code data obliquelyfor the purpose of distributing successive errors” for the purpose ofcomparison so as to obtain the effect of “the perfect product codeformed by appending inner-code (PI) data in the horizontal direction andouter-code (PO) data in the vertical direction”, perfection of theproduct code is impaired, and correction performance cannot be improvedby repeating correction using inner- and outer-code data in such a case.

[0214] 4) Except for interleave between a plurality of ECC blocks, datacorrespondence in the ECC blocks and physical sector data matches thatof the existing DVD standards:

[0215] correspondence between physical sector data and ECC block datafor respective rows including PI; and

[0216] interleaved arrangement of PO in ECC blocks to respectivephysical sectors.

[0217] In this manner, some of the ECC block generation process(generation of PI and PO, and the like) and error correction processesin a reproduction apparatus or recording/reproduction apparatus havingcompatible functions between the existing DVD and next-generation DVDcan be used common to those used upon using an existing DVD disk(medium), and the processing routines and circuits of the reproductionapparatus or recording/reproduction apparatus having compatiblefunctions between existing DVDs and next-generation DVD can besimplified.

[0218] 5) Since a data ID is arranged at the head of physical sectordata as in the existing DVD standards, the access control and sectoraddress detection/confirmation processes in a reproduction apparatus orrecording/reproduction apparatus having compatible functions betweenexisting DVDs and next-generation DVDs can be commonly used, thussimplifying control in the apparatus.

[0219] 6) Since the total of the number of rows including PI (the numberof fourth data units) and the number of PO rows (the number of fifthdata units) included in the physical sector (first data unit) is aninteger multiple of n, all data contained in one physical sector can beuniformly distributed (interleaved and arranged) in all correspondingECC blocks. Since all data can be evenly arranged in the ECC blocks, aninterleave process to the ECC blocks can be facilitated, and equalerror-correctable burst error lengths can be obtained independently ofthe positions on the optical disk, thus preventing adverse influences ofburst errors on reproduced information. That is, since an interleaveprocess is made to alternately record n product code data items onrespective rows, uniform burst error correction performance can beobtained. Hence, there is no locally weak burst error correctionperformance portion. Even when an interleave process for alternatelyarranging data is done, all the sectors can have equal sector lengths.

[0220] 7) All the physical sectors have the same number of PO data itemsto have equal physical sector sizes, and the following merits can beobtained.

[0221] In the prior art, in order to interleave a plurality of productcodes and to distribute outer-code parity data in respective rows,outer-code parity rows must be inserted in a plurality of sectors.Hence, a set of a plurality of sectors must be recorded, or twodifferent types of sectors, i.e., sectors with and without parity datamust be prepared.

[0222] According to the present invention, a rewrite can be made foreach sector. Especially, since an exchange process of defective sectorscan be done for respective sectors, the reserve sector size required forthe exchange process can be reduced. Also, since the area, use of whichis disabled due to defects, can be reduced, the disk use efficiency canbe improved. Also, as sector identification data (ID) to be assigned torespective sectors can be recorded at equal intervals in recording data,the ID can be easily detected and reproduced.

[0223] In the invention described above, for example, n=2 is set. Incorrespondence with the SOBU size, “2 ECC blocks=32 physical sectors” isset as a basic unit, and all data in 32 physical sectors is assigned to2 ECC blocks in the basic unit to assure full compatibility with thestream standards. Also, the recording/reproduction process of a datarecording apparatus complying with the stream standards can besimplified.

[0224] <2>Furthermore, a Sixth Data Unit is Defined as Follows.

[0225] A sixth data unit (e.g., byte unit) obtained by furthersegmenting the fourth data unit (row) is defined. Since “fifth data unit=PO for one row” has already been defined, “sixth data unit =recordinginterleave unit across rows” is defined to avoid confusion.

[0226] The information recording medium of the present inventioncomprises a physical sector area where sixth data units selected in turnfrom different fourth data units are recorded. The information recordingapparatus and method of the present invention select sixth data units inturn from different fourth data units, and record them on the physicalsector area of the information recording medium. The informationreproduction apparatus and method of the present invention reproduce thephysical sector area on which sixth data units selected in turn fromdifferent fourth data units are recorded.

[0227] The relationship between the aforementioned data units is asfollows. fourth data unit ⊃ sixth data unit (row including PI) (byteunit)

[0228] The point of the aforementioned invention is as follows.

[0229] Errors can be distributed by recording interleave (zigzagrecording) among rows in a single physical sector.

[0230] The effects of the present invention are as follows.

[0231] Conventionally, recording is done in the same direction asinner-code data. If successive data items have error correlation, a runof a plurality of bytes may readily cause errors at the same time, andit is highly likely to disable correction of inner-code data. As aresult, the error correction performance is lowered considerablycompared to a case wherein random errors are assumed. When the entireproduct code is obliquely recorded to distribute errors, a plurality ofsectors may simultaneously cause errors.

[0232] The error characteristics of reproduced data have errorcorrelation in successively recorded data items due to the influence ofdust or the like. If error correlation is present, successive errorsreadily occur compared to a case wherein it is assumed that errors occurrandomly. In order to distribute errors that occur successively todifferent inner-code data, the recording direction is set in a zigzagpattern with respect to the direction of inner-code data. As a result,since the number of correctable inner-code data items increases, theerror correction performance can be improved. Since the zigzag patternof the recording direction is limited to the range of one sector,successive errors never spread to a plurality of sectors. Hence, aplurality of sectors can be avoided from causing errors due to seriouserrors.

[0233] <3>Moreover, Physical Sector Information and Logical SectorInformation are Defined as Follows.

[0234] User information recorded in a physical sector that forms thefirst data unit is defined as physical sector information. The minimumunit of user information transferred in a data recording apparatus ordata reproduction apparatus, or the minimum unit of user informationtransferred in the data recording apparatus or between the datareproduction apparatus and external device is defined as logical sectorinformation.

[0235] The information recording medium of the present inventioncomprises a physical sector area that records data which is generated sothat the contents of the physical sector information match those of thelogical sector information. The information recording apparatus of thepresent invention generates and records data so that the contents of thephysical sector information match those of the logical sectorinformation. The information reproduction apparatus and method of thepresent invention reproduce the physical sector area that records datawhich is generated so that the contents of the physical sectorinformation match those of the logical sector information. In thismanner, the physical sector information can match the logical sectorinformation.

[0236] The effects of the aforementioned invention are as follows.

[0237] 1) Data access can be made for respective logical sectors. Whenthe error rate of a reproduced signal from the optical disk is low, anderror correction of respective rows in the physical sector can be madeusing only PI information, error-free (accurate) physical sectorinformation can be read out without using PO information. Hence, whenECC blocks are formed so that logical sector information matchesphysical sector information as in the present invention, if the errorrate of a reproduced signal from the optical disk is low, one logicalsector information can be read out by only reproducing one physicalsector data from the optical disk without using any PO information, thusallowing very easy data access.

[0238] In the present invention, a data ID containing sector addressinformation is arranged at the head position in each physical sectordata item. In general, this data ID is used to access data recorded onthe optical disk. According to the present invention, since the contentsof the logical sector information match those of the physical sectorinformation, logical sector information can be recorded in this data ID.Hence, as logical sector address information in physical sector data canbe directly accessed to access the logical sector position designated bythe application or logical layer, the data access time can be greatlyshortened.

[0239] 2) According to the present invention, data continuity can beeasily assured. In the format of the application standards, AVinformation and stream information are successively recorded in theorder of logical sector addresses. In the present invention, since thecontents of logical sector information match those of physical sectorinformation, logical sector information can be recorded in the data ID.As a result, the order AV information and stream information to berecorded or reproduced in the order logical sector addresses arearranged matches the order of physical sector addresses, which is set inaccordance with the order physical sectors are arranged on the opticaldisk. Consequently, an unnecessary access process (track jump process)upon successively recording or reproducing AV information and streaminformation on/from the optical disk can be greatly reduced, andcontinuity of AV information and stream information upon recording orreproduction can be easily assured.

[0240] 3) According to the present invention, a defect process can beeasily done for respective sectors.

[0241] In the prior art, when a plurality of product codes is generatedin an integer number of sectors and the codes are interleaved, data of aplurality of sectors is mixed together upon recording. Hence, ifsuccessive burst errors have occurred due to defects, errors may besimultaneously produced in a plurality of sectors. Normally, since thepresence/absence of errors is finally checked for each sector, manysectors readily become defective at the same time. Also, since logicaladdresses are nonuniformly recorded, recorded data cannot be efficientlysearched.

[0242] According to the present invention, when uncorrectable errorshave occurred due to defects, the residual errors can be prevented fromspreading after correction. As a result, the number of sectors thatcontain errors can be minimized. When a specific sector is searched forwhile reproducing data, the target position can be easily found due tocontinuity of sector numbers.

[0243] <4>Furthermore, the information recording medium of the presentinvention comprises a physical sector area that records data which isgenerated, so that the arrangement of at least some data in at least oneof a plurality of ECC blocks matches the contents of logical sectorinformation. The information recording apparatus and method of thepresent invention generate and record data so that the arrangement of atleast some data in at least one of a plurality of ECC blocks matches thecontents of the logical sector information. The information reproductionapparatus and method of the present invention reproduce the physicalsector area that records data which is generated, so that thearrangement of at least some data in at least one of a plurality of ECCblocks matches the contents of the logical sector information. In thisway, the contents of the logical sector information match the dataarrangement in an ECC block.

[0244] The effect of the aforementioned invention is as follows.

[0245] Processes until formation of ECC blocks for logical sectorinformation, which is to be transferred in a data recording apparatus orbetween a data reproduction apparatus and external device, match thoseuntil formation of ECC blocks in the existing DVD. Hence, some of theECC block generation processes (generation of PI and PO, and the like)and error correction processes in a reproduction apparatus orrecording/reproduction apparatus having compatible functions betweenexisting DVDs and next-generation DVDs can be used common to those usedupon using an existing DVD disk, and the processing routines andcircuits of the reproduction apparatus or recording/reproductionapparatus having compatible functions between existing DVDs andnext-generation DVDs can be simplified.

[0246] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. An information recording medium comprising: amanagement area where management information is recorded; and aplurality of physical sector areas used to record a plurality ofphysical sector data blocks, which are generated by combining some datacontained in a plurality of ECC blocks.
 2. A medium according to claim1, wherein the plurality of ECC blocks as a source of the plurality ofphysical sector data blocks to be recorded in said plurality of physicalsector areas is generated via a predetermined process, and thepredetermined process generates the plurality of independent ECC blocksby: generating sector data formed of a first number of bytes; generatinga sector block by combining a plurality of sector data items; generatinga plurality of segmented blocks by segmenting the sector block; andindividually appending parity data to the plurality of segmented blocks.3. A medium according to claim 1, wherein the plurality of ECC blocks asa source of the plurality of physical sector data blocks to be recordedin said plurality of physical sector areas is generated via apredetermined process, and the predetermined process generates theplurality of independent ECC blocks by: generating sector data whichcontains a data ID and is formed of a first number of bytes; generatinga sector block by combining a plurality of sector data items; generatinga plurality of segmented blocks by segmenting the sector block;generating outer-code parity data by encoding data in a columndirection, which forms each segmented block; generating inner-codeparity data by encoding data in a row direction, which forms eachsegmented block; and individually appending the generated outer- andinner-code parity data to each segmented block.
 4. A medium according toclaim 1, wherein the plurality of ECC blocks as a source of theplurality of physical sector data blocks to be recorded in saidplurality of physical sector areas is generated via a predeterminedprocess, and the predetermined process generates the plurality ofindependent ECC blocks by: generating sector data which contains a dataID and is formed of a first number of bytes; generating re-arrangedsector data by re-arranging data contained in the sector data topredetermined positions; generating a sector block by combining aplurality of re-arranged sector data items; generating a plurality ofsegmented blocks by segmenting the sector block; generating outer-codeparity data by encoding data in a column direction, which forms eachsegmented block; generating inner-code parity data by encoding data in arow direction, which forms each segmented block; and individuallyappending the generated outer- and inner-code parity data to eachsegmented block.
 5. A medium according to claim 4, wherein each physicalsector data block recorded on said physical sector area is formed of aset of data lines each of which is made up of a portion of the sectordata and a portion of the inner-code parity data, and consists of asecond number of bytes, and data lines each of which is made up of onlya portion of the outer-code parity data and consists of the secondnumber of bytes, and a total number of data lines of the set is aninteger multiple of the number of ECC blocks.
 6. A medium according toclaim 4, wherein each physical sector data block recorded on saidphysical sector area contains the data ID, and has a data structure inwhich the data ID is arranged at a specific position.
 7. A mediumaccording to claim 4, wherein each physical sector data block recordedon said physical sector area contains the data ID, and has a datastructure in which the data ID is arranged at a head position, and adata line made up of only a portion of the outer-code parity data isarranged as a final line.
 8. A medium according to claim 1, wherein saidphysical sector area is an area on which data extracted in turn from thephysical sector data block according to a predetermined rule is recordedin turn.
 9. A medium according to claim 1, wherein said physical sectorarea is an area on which data alternately extracted from different datalines in the physical sector data block is recorded in turn.
 10. Amedium according to claim 4, wherein physical sector information whichindicates the physical sector data block to be recorded on said physicalsector area corresponds to logical sector information which indicatesthe sector data.
 11. A medium according to claim 10, wherein anarrangement of at least some data of the plurality of ECC blocks as asource of the plurality of sector data blocks to be recorded on saidplurality of physical sector areas corresponds to logical sectorinformation.
 12. An information recording apparatus for recordinginformation on an information recording medium, comprising: generationsection configured to generating a plurality of ECC blocks; andrecording section configured to generating a plurality of physicalsector data blocks by combining some data contained in the plurality ofECC blocks, and recording the plurality of physical sector data blockson a plurality of physical sector areas on the information recordingmedium.
 13. An apparatus according to claim 12, wherein said generationsection generate the plurality of independent ECC blocks by: generatingsector data which contains a data ID and is formed of a first number ofbytes; generating re-arranged sector data by re-arranging data containedin the sector data to predetermined positions; generating a sector blockby combining a plurality of re-arranged sector data items; generating aplurality of segmented blocks by segmenting the sector block; generatingouter-code parity data by encoding data in a column direction, whichforms each segmented block; generating inner-code parity data byencoding data in a row direction, which forms each segmented block; andindividually appending the generated outer- and inner-code parity datato each segmented block.
 14. An apparatus according to claim 13, whereinsaid recording section alternately extracts data from different datalines in the physical sector data block, and records the extracted datain turn on the physical sector area.
 15. An apparatus according to claim13, wherein said recording section records the physical sector datablock on the physical sector area with physical sector information thatindicates the physical sector data block corresponding to logical sectorinformation that indicates the sector data.
 16. An apparatus accordingto claim 15, wherein said recording section records the physical sectordata block on the physical sector area with an arrangement of at leastsome data of the plurality of ECC blocks corresponding to logical sectorinformation.
 17. An information reproduction apparatus for reproducingan information recording medium which comprises a plurality of physicalsector areas on which a plurality of physical sector data blocksgenerated by combining some data contained in a plurality of ECC blocksis recorded, comprising: read-out section configured to reading out theplurality of physical sector data blocks from the plurality of physicalsector areas on the information recording medium; and reproductionsection configured to reproducing data by generating the plurality ofECC blocks from the plurality of readout physical sector data blocks.18. An apparatus according to claim 17, wherein said reproductionsection generates the plurality of ECC blocks via a predeterminedprocess, the predetermined process generates the plurality ofindependent ECC blocks by: generating sector data which contains a dataID and is formed of a first number of bytes; generating re-arrangedsector data by re-arranging data contained in the sector data topredetermined positions; generating a sector block by combining aplurality of re-arranged sector data items; generating a plurality ofsegmented blocks by segmenting the sector block; generating outer-codeparity data by encoding data in a column direction, which forms eachsegmented block; generating inner-code parity data by encoding data in arow direction, which forms each segmented block; and individuallyappending the generated outer- and inner-code parity data to eachsegmented block, and said reproduction means reproduces the sector databy utilizing the predetermined process.
 19. An apparatus according toclaim 18, wherein the physical sector data block read out by said read-out section is formed of a set of data lines each of which is made up ofa portion of the sector data and a portion of the inner-code paritydata, and consists of a second number of bytes, and data lines each ofwhich is made up of only a portion of the outer-code parity data andconsists of the second number of bytes, and a total number of data linesof the set is an integer multiple of the number of ECC blocks, eachphysical sector data block recorded on said physical sector areacontains the data ID, and has a data structure in which the data ID isarranged at a head position, and a data line made up of only a portionof the outer-code parity data is arranged as a final line, and saidreproduction section reproduces the data ID from the head position ofeach physical sector data block.
 20. An apparatus according to claim 19,wherein the physical sector area read out by said read-out sectionrecords data alternately extracted from different data lines in thephysical sector data block, and said reproduction section reproduces thephysical sector data block read out from the physical sector area undera condition that the data alternately extracted from the different datalines is recorded.